package cn.newtouch.util.utils;

import java.util.concurrent.ExecutorService;
import java.util.concurrent.TimeUnit;

/**
 * 线程相关工具类.
 * 
 * @author calvin
 */
public class Threads
{

    /**
     * sleep等待,单位为毫秒,忽略InterruptedException.
     */
    public static void sleep(long millis)
    {
        try
        {
            Thread.sleep(millis);
        }
        catch (InterruptedException e)
        {
            // Ignore.
        }
    }

    /**
     * sleep等待,忽略InterruptedException.
     */
    public static void sleep(long duration, TimeUnit unit)
    {
        try
        {
            Thread.sleep(unit.toMillis(duration));
        }
        catch (InterruptedException e)
        {
            // Ignore.
        }
    }

    /**
     * 按照ExecutorService JavaDoc示例代码编写的Graceful Shutdown方法. 先使用shutdown,
     * 停止接收新任务并尝试完成所有已存在任务. 如果超时, 则调用shutdownNow,
     * 取消在workQueue中Pending的任务,并中断所有阻塞函数. 如果仍人超時，則強制退出.
     * 另对在shutdown时线程本身被调用中断做了处理.
     */
    public static void gracefulShutdown(ExecutorService pool,
            int shutdownTimeout, int shutdownNowTimeout, TimeUnit timeUnit)
    {
        pool.shutdown(); // Disable new tasks from being submitted
        try
        {
            // Wait a while for existing tasks to terminate
            if (!pool.awaitTermination(shutdownTimeout, timeUnit))
            {
                pool.shutdownNow(); // Cancel currently executing tasks
                // Wait a while for tasks to respond to being cancelled
                if (!pool.awaitTermination(shutdownNowTimeout, timeUnit))
                {
                    System.err.println("Pool did not terminated");
                }
            }
        }
        catch (InterruptedException ie)
        {
            // (Re-)Cancel if current thread also interrupted
            pool.shutdownNow();
            // Preserve interrupt status
            Thread.currentThread().interrupt();
        }
    }

    /**
     * 直接调用shutdownNow的方法, 有timeout控制.取消在workQueue中Pending的任务,并中断所有阻塞函数.
     */
    public static void normalShutdown(ExecutorService pool, int timeout,
            TimeUnit timeUnit)
    {
        try
        {
            pool.shutdownNow();
            if (!pool.awaitTermination(timeout, timeUnit))
            {
                System.err.println("Pool did not terminated");
            }
        }
        catch (InterruptedException ie)
        {
            Thread.currentThread().interrupt();
        }
    }

}
